CHEMBL5733666

PDE2 Assay B: The activity of the compounds in accordance with the present invention as PDE2 inhibitors may be readily determined using a fluorescence polarization (FP) methodology (Huang, W., et al., J. Biomol Screen, 2002, 7: 215). In particular, the compounds of the following examples had activity in reference assays by exhibiting the ability to inhibit the hydrolysis of the phosphate ester bond of a cyclic nucleotide. Any compound exhibiting a Ki (inhibitory constant) of about 50 μM or below would be considered a PDE2 inhibitor as defined herein. The PDE2 inhibitory activity of the compounds of the present invention was determined in accordance with the following experimental method. Rhesus PDE2A3 was amplified from rhesus macaque brain cDNA (Biochain Institute, Hayward, Calif.) using primers based on human PDE2A sequence (accession NM_002599.3) where the forward primer containing a Kozak consensus was 5′-gccaccatggggcaggcatgtggc-3′ and the reverse primer was 5′-tcactcagcatcaaggctgca-3′. Amplification with Easy-A High-Fidelity PCR cloning enzyme (Stratagene, La Jolla, Calif.) was 95° C. for 2 minutes followed by thirty three cycles of 95° C. for 40 seconds, 52° C. for 30 seconds, and 72° C. for 2 minutes 48 seconds. Final extension was 72° C. for 7 minutes. The PCR product was TA cloned into pcDNA3.3-TOPO (Invitrogen, Carlsbad, Calif.) according to standard protocol. A consensus sequence was developed from multiple clones and then deposited into GenBank (EU812167). AD293 cells (Stratagene, La Jolla, Calif.) with 70-80% confluency were transiently transfected with rhesus PDE2A3/pcDNA3.3-TOPO using Lipofectamine 2000 according to manufacturer specifications (Invitrogen, Carlsbad, Calif.). Cells were harvested 48 hours post-transfection and lysed by sonication (setting 3, 10×5 sec pulses) in a buffer containing 20 mM HEPES pH 7.4, 1 mM EDTA and Complete Protease Inhibitor Cocktail Tablets (Roche, Indianapolis, Ind.). Lysate was collected by centrifugation at 75,000×g for 20 minutes at 4° C. and supernatant utilized for evaluation of PDE2 activity. The fluorescence polarization assay for cyclic nucleotide phosphodiesterases was performed using an IMAP® FP kit supplied by Molecular Devices, Sunnyvale, Calif. (product #R8139). IMAP® technology has been applied previously to examine the effects of phosphodiesterase inhibitors (Huang, W., et al., J. Biomol Screen, 2002, 7: 215). Assays were performed at room temperature in 384-well microtiter plates with an incubation volume of 20.2 μL. Solutions of test compounds were prepared in DMSO and serially diluted with DMSO to yield 8 μL of each of 10 solutions differing by 3-fold in concentration, at 32 serial dilutions per plate. 100% inhibition is determined using a known PDE2 inhibitor, which can be any compound that is present at 5,000 times its Ki value in the assay described below, such as Bay 60-7550 (Ki-˜0.2 nM) at 1 μM concentration for 100% inhibition. Bay 60-7550 was obtained from Axxora via Fisher Scientific (cat# ALX-270-421-M025/cat# NC9314773). Put another way, any compound with Ki of ˜0.2 to about 2 nM could be used at 1 to 10 μM. 0% of inhibition is determined by using DMSO (1% final concentrations). The measurements are done in Laboratory B.